项目名称： 零轴肩压入零减薄搅拌摩擦焊焊缝组织性能特性及形成机理研究

项目编号： No.51505471

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 机械、仪表工业

项目作者： 张会杰

作者单位： 东北大学

项目金额： 22万元

中文摘要： 常规搅拌摩擦焊（FSW）中出现的焊缝减薄现象对接头成形质量及服役可靠性都存在不利影响。现有消除FSW焊缝减薄现象的方法普遍存在效率低、质量差、可适用范围窄等问题，为此，本项目提出了一种新型零减薄FSW方法，能够在焊具轴肩压入量为零的工艺条件下，一次性获得优质零减薄FSW接头，从而为结构件高效率、高质量的零减薄焊接开辟了新的技术途径。为了深刻阐明这一新型零减薄FSW工艺的特性和机理，本项目开展了零轴肩压入零减薄FSW焊缝组织性能特性及形成机理研究。首先探索焊具轴肩的间接热机作用对焊缝微观组织演变及接头力学行为的影响特征和机制，明晰焊缝组织性能特性，而后建立能够真实反映零减薄FSW产热特征的轴肩双面摩擦热源模型，进行焊接热-流模拟分析，阐明工艺特性的本质原因，揭示焊缝形成机理。研究成果可望为此新型零减薄FSW工艺的优化控制提供理论依据，促进保形精确焊接技术的发展，具有较大的理论与实际意义。

中文关键词： 零减薄搅拌摩擦焊；力学行为；组织演变；焊缝形成机理

英文摘要： The weld thinning phenomenon occurring in conventional friction stir welding (FSW) has negative effect on the formation quality and serviceable reliability of FSW joints. The existing methods for solving the weld thinning problem in FSW exhibit some universal deficiencies, such as low efficiency, low quality and narrow applicable range. Motivated by this problem, the present project proposes a novel non-thinning FSW process, in which the high quality non-thinning friction stir weld can be one-time produced at a zero shoulder plunge depth. This novel process opens a brand new pathway for the high-efficiency and high-quality non-thinning FSW of structures. To deeply elucidate the characteristics and mechanisms of the novel non-thinning FSW process, the microstructure-property characteristics and formation mechanism of non-shoulder-plunge and non-thinning friction stir weld is investigated in the present project. Firstly, the features and mechanisms of the indirect thermal-mechanical effects of tool shoulder on microstructure evolution and mechanical behavior of FSW joints are explored to illuminate the microstructure-property characteristics of non-thinning FSW. After this, a double-surface frictional heat source model of tool shoulder, which can truly reflect the heat generation features of non-thinning FSW, is developed, and then the thermal and flow fields of non-thinning FSW are simulated. The intrinsic reasons for the process characteristics are therefore illustrated, and the weld formation mechanism of non-thinning FSW is revealed in nature. The project is expected to provide theoretical basis for the optimal control of non-thinning FSW, and is also beneficial to promote the development of accurately shaped welding technique. So this project is significative for both theory and practical application.

英文关键词： Non-thinning friction stir welding;Mechanical behavior;Microstructure evolution;Weld formation mechanism